The technology relates to a following-start control apparatus that so automatically starts an own vehicle as to follow the start of a preceding vehicle.
An adaptive cruise control (ACC) system has been known that performs a constant-speed travel control and a following-travel control. The ACC system performs the constant-speed travel control that causes an own vehicle to keep a set vehicle speed when a preceding vehicle is absent, and performs, when the preceding vehicle is detected, the following-travel control that causes the own vehicle to follow the preceding vehicle while keeping an inter-vehicular distance directed to the following travel between the own vehicle and the preceding vehicle.
A recent ACC system extends a range in which the ACC system is applied to a low speed range, such as a range that covers zero km/h, to allow for a function of following the preceding vehicle during a traffic jam. Such an ACC system so stops the own vehicle automatically as to follow the stop of the preceding vehicle set as a target to follow when detecting the stop of the preceding vehicle, and so starts the own vehicle automatically as to follow the start of the preceding vehicle when detecting the start of the preceding vehicle thereafter.
In a situation in which the preceding vehicle stops and starts repeatedly, such as during a traffic jam, an inter-vehicular distance between the own vehicle and the preceding vehicle may sometimes become short due to a sudden stop of the preceding vehicle, a delay in perception of a driver, or any other factor. This concern occurs when a response time required for the own vehicle to start automatically is set to a response time which is about the same as that used upon a normal following-travel operation. In contrast, setting the response time longer raises a concern that the inter-vehicular distance between the own vehicle and the preceding vehicle becomes longer, thus impairing the performance of following the preceding vehicle.
To address these concerns, Japanese Unexamined Patent Application Publication (JP-A) No. 2015-214309 discloses a technique in which a timing of starting an own vehicle after detecting the start of a preceding vehicle is set on the basis of an inter-vehicular distance and a relative speed both between the own vehicle and the preceding vehicle. The technique disclosed in JP-A No. 2015-214309 sets, with use of a map in which an inter-vehicular distance and a relative speed are set in advance, the timing of starting the own vehicle on the basis of the inter-vehicular distance and the relative speed that are both after the start of the stopped preceding vehicle where a speed of the own vehicle is zero km/h, and starts the own vehicle at the thus-set timing.